JPH04370502A - Magnetic recorder - Google Patents

Abstract

PURPOSE:To easily detect the operation abnormality of the magnetic head of a magneto-optical disk drive device, etc., through simple configuration. CONSTITUTION:The signal of an RCPC area Da attached to the front part of a write-in signal Si is outputted by switching a switching circuit 22 into a conductive state by a gate signal Sg from a control part 23 as synchronizing with duration in which it flows to the magnetic head 10. Whether the operating state of the magnetic head 10 is abnormal or not is discriminated from the value of this detected voltage by comparators 36, 38 to constitute a window comparator, and its output signal So is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording device suitable for application to magneto-optical disk drives and the like.

0002

2. Description of the Related Art Conventionally, in a magnetic disk drive device that writes information to or reads recorded information from a magnetic recording medium such as a floppy disk or a hard disk, the operation of a magnetic head is monitored when information is written. For example, in a hard disk drive device, a potential difference generated in a resistance detection circuit in which a resistor or the like is inserted in a magnetic head drive circuit or the like is detected, or a flyback voltage of a magnetic head during switching is also detected.
The operation of the magnetic head is monitored from this potential difference or flyback voltage value. In this way, conventional magnetic disk drive devices detect abnormalities such as disconnections and short circuits in the coil of the magnetic head and perform processing to stop the write operation.

0003

By the way, in a magneto-optical disk drive device using a magneto-optical disk, the current applied to the magnetic head during recording is, for example, 400 mA to 400 mA to perform overwrite recording. 500m
A, it is a relatively large current drive, and the current applied during recording of the hard disk drive device, for example, 20mA to 3
It is 0mA.

Therefore, it is difficult to apply a resistance detection circuit or a flyback voltage detection circuit like a conventional hard disk drive to a recent magneto-optical disk drive as it is in terms of signal processing.
Currently, in recent magneto-optical disk drive devices, the recording operation of the magnetic head is not monitored. In addition, when using a resistance detection circuit, the voltage drop is detected from the current flowing in the write signal supplied to the magnetic head.
It is conceivable that the processing time required to detect an abnormality from this detection may cause an adverse effect on the write signal, for example, inconveniences such as omission of reproduced information.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an excellent magnetic recording device that can easily detect malfunctions in the magnetic head and peripheral circuits of a magneto-optical disk drive device etc. with a simple configuration. With the goal.

[0006]

Means for Solving the Problems The magnetic recording apparatus of the present invention includes, for example, as shown in FIGS. 1 to 3, a magnetic head (10) to which an information signal into which a detection signal is inserted is supplied; A current detection means (Ra
), the current detection means (Ra) when the information signal (Si) is energized, and the coils (10a, 10) of the magnetic head (10).
The detection voltage at the connection point with b) is supplied, and the switching means (2) makes the detection voltage conductive or non-conductive.
2) and drive control that switches the switching means (22) to conduction in synchronization with the input of the detection signal (Da) included in the information signal (Si) to the magnetic head (10) to derive only the detection voltage. means (23); operation identification means (36, 38) for identifying the operating state of the magnetic head (10) and peripheral circuits from the value of the detected voltage; It is provided with operation identification means (36, 38) for identifying the state.

[0007]

[Operation] According to the magnetic recording device of the present invention, the switching means (22) is switched to conduction in synchronization with the supply of the detection signal included in the information signal to the magnetic head (10), and only the detection voltage is derived. Based on the value of this detection voltage, the magnetic head (10
) and peripheral circuits, it becomes possible to detect operational abnormalities with a simple configuration.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magnetic recording apparatus of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a magneto-optical disk drive device, in which a magnetic head 10 is provided. The magnetic head 10 includes a pair of coils 10a and 10b, each having a diode connected in parallel. A resistor Ra is connected in series between one end of each of the coils 10a and 10b and a power supply terminal +VDD. The other end of the coil 10a is connected to the source of the drive FET 12, and similarly the other end of the coil 10b is connected to the source of the drive FET 14. The drains of each of the drive FETs 12 and 14 are grounded, and the gate of the drive FET 12 is supplied with a write signal Si, which will be described in detail later, from an amplifier 16a. Further, the gate of the drive FET 14 receives a write signal Si whose phase is inverted from the inverter 16b.
is supplied.

A smoothing low-pass filter (LPF) 20 consisting of a resistor R and a capacitor C is connected to the connection point between the resistor Ra and the coils 10a and 10b, and its output is connected to the fixed contact 22a of the switching circuit 22. supplied to The movable contact 22b of this switching circuit 22 has
RCPC area (signal) Da for phase compensation attached before (time axis) recording information (signal) Db of write signal Si
This RCPC area (signal) D
In order to turn on (turn on) the switching circuit 22 in synchronization with a, a control section 23 is provided that supplies a gate signal Sg generated by counting clock pulses from a timing generator or the like, for example.

The movable contact 22b of the switching circuit 22 is supplied to a sample-and-hold circuit 24 composed of a resistor R, a capacitor C, an amplifier, etc., and then this output signal is supplied to a comparator 36 and a comparator 38. . This comparator 36 is set to a high threshold level Vref1, and the comparator 38
is set to a threshold level Vref2 that is lower than the threshold level Vref1, and constitutes a so-called window comparator. This comparator 3
6 and the output signal of the comparator 38 are CP (not shown).
It is supplied to U etc.

FIG. 2 shows the write signal Si. The write signal Si is an example of recording on a magneto-optical disk, and one recording round is divided into a plurality of sectors, for example, 4 sectors.
2 sectors/tracks
Recording or playback is performed in sector units. As shown in the figure, one sector includes a single frequency RCPC (read clock phase control) area (signal) Da before (time axis) recording information (signal) Db.
is formed. This RCPC area (signal) Da is used for signal processing such as power control of the laser beam during recording, AGC during playback, and phase compensation, and it is used for signal processing such as AGC and phase compensation during playback. Since it needs to be written, its highest frequency is used. This RCPC area (signal) Da is
When the magnetic head 10 (coils 10a, 10b) is energized, it is detected as a voltage drop across the resistor Ra, and the operating state of the magnetic head 10 is identified by comparators 36, 38 from the value of the detected voltage drop. That is, the magnetic head 10
, the drive FETs 12 and 14, and the peripheral circuits such as the amplifier 16a and the inverter 16b.

Next, the operation of the above configuration will be explained. Coil 10a and coil 10b of magnetic head 10
A write signal Si from the amplifier 16a and the inverter 16b is supplied through the drive FET 12 and the drive FET 14. Here, the coils 10a and 10b generate a magnetic field according to the level of the write signal Si, and overwrite writing is performed on a magneto-optical disk (not shown) by magnetic modulation.

At this time, depending on the switching of the drive FETs 12 and 14, the coils 10a and 10b of the magnetic head 10
An energizing current I flows through the resistor Ra, and a detection signal of the voltage drop across the resistor Ra is supplied to the fixed contact 22a of the switching circuit 22 through the LPF 20. Here, the switching circuit 22
While the RCPC area Da of the write signal Si shown in FIG. 2 is supplied from the control unit 23 to the movable contact 22b of (
A gate signal Sg is supplied in synchronization only with the time axis), and the circuit becomes conductive (on). Therefore, only the RCPC area Da is output from the switching circuit 22 as a time average value from the LPF 20. Note that the supplied gate signal Sg may be supplied in an interval shorter than the time axis of the RCPC area Da, and an abnormal operation may be detected in this interval.

[0014] This time average value RCPC area Da
The detection signal, which is the voltage drop of
After being sampled and held through the comparator 36
, 38 at the same time. This comparator 36
, 38, they are compared with the set high and low reference threshold levels Vref1 and Vref2, respectively. That is, it is determined whether or not Vref2<SO<Vref1. The comparator 36 outputs the output signal So when the threshold level is equal to or higher than the threshold level Vref1, and in this case, for example, the output signal So is
Abnormal operation of drive FET12, 14, etc. or drive FE
A voltage higher than a predetermined voltage is applied to the gates of T12 and T14,
This shows an operational abnormality in which a predetermined abnormal current I flows through the coils 10a and 10b of the magnetic head 10. Further, the comparator 38 sends out an output signal So when the threshold level Vref2 is lower than the threshold level Vref2, and in this case, the output signal So is, for example,
This indicates an abnormality in which the energizing current I is not flowing through the coils 10a and 10b due to disconnection, short circuit, etc. in the coils 10a and 10b. The output signals of the comparators 36 and 38 are supplied to a CPU (not shown), etc., and the CPU makes a predetermined determination and processes the same. For example, this includes stopping the supply of write signals to the magneto-optical disk by the magnetic head 10, and displaying the same.

In this way, the switching circuit 22 is turned on in synchronization only while the detection signal of the RCPC area Da included in the write signal Si is input to the magnetic head 10, and the detection voltage of only the RCPC area Da is switched on. In order to identify the operating state of the magnetic head 10 from the detected voltage value using the comparators 36 and 38, the magnetic head 10 and drive FET provided in the magneto-optical disk device, etc.
12, 14, etc. can be detected with a simple configuration.

[0016] Furthermore, the RCP added before the recording information Db
In order to identify the operating state of the magnetic head 10 from the value of the detected voltage when the C area Da is energized to the magnetic head 10 and detect an abnormality in the operation of the magnetic head 10, the magnetic Head and drive FET1
The operational abnormalities No. 2 and 14 can be easily determined from only the RCPC area Da without affecting the recorded information Db.

FIG. 3 shows the configuration of another embodiment. In another embodiment shown in FIG. 3, the coil 10 of the magnetic head 10
A and 10b are replaced by a magnetic head composed of one coil 52 driven by an amplifier 50 with a constant current. Detection of abnormal operation of the coil 52 may be performed in the same manner as in the embodiment described above.

[0018] In the above-mentioned embodiments, the application to a magneto-optical disk drive device has been described, but the present invention is not limited thereto. It can also be applied to other devices that employ magnetic heads. Further, in the above embodiment, in order to obtain the output signal So, the LPF2
0, the switching circuit 22, the control unit 23, the sample and hold circuit 24, and the comparators 36 and 38 are used; however, the present invention is not limited to this.
) and perform similar signal processing.

[0019]

As can be understood from the above description, according to the magnetic recording device of the present invention, the switching means is switched to conduction in synchronization with the input of the detection signal included in the information signal to the magnetic head. Since only the voltage is derived and the operating state of the magnetic head is identified from the value of this detected voltage, it has the effect that abnormal operation can be detected with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a magnetic recording device of the present invention.

FIG. 2 is a waveform diagram of a recording signal supplied to a magnetic head in the embodiment.

FIG. 3 is a circuit diagram showing the configuration of main parts in another embodiment.

[Explanation of symbols]

10 Magnetic head 10a, 10b coil 22 Switching circuit 22a Fixed contact 22b Movable contact 23 Control section 24 Sample and hold circuit 36, 38 Comparator Da RCPC area (signal) Db Recorded information (signal) Ra resistor Si write signal

Claims (1)

[Claims] 1. A magnetic head to which an information signal into which a detection signal is inserted is supplied, a current detecting means connected in series with a coil of the magnetic head to which the information signal is supplied, and a current detecting means when the information signal is energized. A detection voltage is supplied to the connection point between the detection means and the coil of the magnetic head, and a switching means is provided to make the detection voltage conductive or non-conductive, and a switching means is provided in synchronization with the input of the detection signal included in the information signal to the magnetic head. a drive control means for controlling the switching means to be conductive and deriving only the detected voltage; and an operation identification means for identifying the operating state of the magnetic head and peripheral circuits from the value of the detected voltage. Device.